Fourier transform infrared absorption spectrometer

Working principle

ftir is mainly composed of Michaelson interferometers and computers.

The infrared light emitted by the infrared light source S is performed in parallel infrared beam into the interference system, and a bundle of interference is obtained after the interferometer is adjusted. The interference light is passed through the sample SA, The interference signal containing the spectral information reaches the detector D, and the interference signal is changed to the electrical signal by D. The interference signal here is a time function, ie the interference map depicted by the interference signal, which is the moving distance of the moving time or the moving distance of the moving mirror. This interference map is sent to the computer through the A / D converter, and the flash calculation of Fourier transform is obtained by the computer, that is, the infrared spectrum of the wave number is a horizontal coordinate. Then the D / A converter is sent to the plotter to draw the standard infrared absorption spectrum map of people very familiar.

Main parts

Light source

Fourier transform infrared spectrometer requires a continuous wavelength of the light source to emit stable, strong energy and low emissivity. It is usually used in Steve, silicon carbon rods.

Michael interferometer

The core part of the FTIR instrument is Michaelson interferometer.


is also the detector mentioned above, it can generally be two categories: thermal detectors and optical detectors. The working principle of the thermal detector is to place the crystals of some hot spot materials in two metal plates, and when light is irradiated onto the crystal, the crystal surface charge distribution changes, thereby measuring the power of infrared radiation.

record system

Infrared work software, Fourier transform infrared spectrometer infrared spectrum record, processing is generally carried out on a computer.

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